JP2002064272A - Multilayered printed wiring board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered printed wiring board which surely prevents the occurrence of disconnection and short-circuiting and is superior in production efficiency, and to provide a manufacturing method. SOLUTION: In the method for manufacturing the multilayer printed wiring board 1, resinous metal foils 3, which are obtained by sticking insulating resin layers 31 and conductor layers 32, are laminated on both faces of a core substrate, where a through-hole 23 has been made. The insulating resin layer 31 of resin metallic foil 3 is constituted of a resin 311, to which filler 4 is mixed. At lamination of resin metal foil 3 to the core substrate 2, the resin 311 of the insulating resin layer 31 is made to flow into the through-hole 23 of the core substrate 2 and the hole is filed with resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board obtained by laminating metal foil with resin on both sides of a core substrate having through holes, and a multilayer printed wiring board.

[0002]

2. Description of the Related Art Conventionally, there are the following methods for manufacturing a multilayer printed wiring board having a plurality of conductor layers.
That is, in the manufacturing method, first, a core substrate provided with through holes for electrically connecting both surfaces of an insulating substrate is prepared. Next, after filling a resin filler into the through holes of the core substrate, conductor patterns are formed on both surfaces of the core substrate. Next, an insulating resin layer and a conductor layer are sequentially laminated on both surfaces of the core substrate.

However, the method of manufacturing a multilayer printed wiring board requires a step of filling the through hole of the core substrate with the resin filler as described above. Further, after filling, it is necessary to remove the resin filler protruding from the through hole by polishing or the like. Therefore, the above-mentioned manufacturing method has a problem that production efficiency is poor.

[0004] From such a viewpoint, there is a method of manufacturing a multilayer printed wiring board without previously filling a through-hole with a resin filler as shown in FIGS. In the manufacturing method, first, as shown in FIG. 4A, a core substrate 9 provided with a through hole 93 is prepared. The core substrate 9 has conductor patterns 92 on both surfaces of an insulating substrate 91, and the through holes 93 electrically connect these conductor patterns 92.

Next, as shown in FIG. 4B, metal foils 8 with resin are laminated on both surfaces of the core substrate 9. That is, the resin-attached metal foil 8 has an insulating resin layer 81 and a conductor layer 82 stuck on one surface thereof, and the insulating resin layer 81 is arranged in contact with both surfaces of the core substrate 9 so as to face each other. . By applying pressure while heating, the core substrate 9 and the metal foil 8 with resin are joined together, and the resin 8 of the insulating resin layer 81 is bonded.
11 flows into the through holes 93 of the core substrate 9,
It is filled (FIGS. 5C and 5D). Next, the resin 811 is thermally cured.

With this, the metal foil 8 with resin is laminated on the core substrate 9 and the resin 8 is
Since the filling of 11 can be performed, a multilayer printed wiring board excellent in production efficiency can be obtained.

[0007]

However, the above-mentioned method for manufacturing a multilayer printed wiring board has the following problems. That is,
According to the manufacturing method, as described above, the resin 811 of the insulating resin layer 81 of the metal foil 8 with resin flows into the through hole 93. Thereafter, when the insulating resin layer 81 is cured, the resin 811 thermally contracts.

At this time, the resin 811 in the through hole 93 also thermally contracts. Therefore, in the periphery of the through hole 93, the amount of shrinkage differs between a portion having the through hole 93 and a portion not having the through hole 93. Therefore, FIG.
As shown in (D), the insulating resin layer 81 above the through hole 93 is dented, and a concave 829 is also formed on the conductor layer 82 thereabove.

If the amount of depression A is large, the conductor layer 82
In forming a conductor pattern in the above, there is a possibility that defects such as disconnection and short-circuit may occur due to poor exposure or poor etching. As shown in FIG. 5D, the dent amount A is defined as a value corresponding to the amount of the through hole 93 with respect to the conductor layer 82 above the portion where the through hole 93 is not provided.
Shows the amount of depression of the conductor layer 82 above.

The present invention has been made in view of such conventional problems, and reliably prevents the occurrence of disconnection, short circuit, and the like.
An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board excellent in production efficiency, and a multilayer printed wiring board.

[0011]

According to a first aspect of the present invention, there is provided a multi-layer printing method in which a resin-coated metal foil obtained by laminating an insulating resin layer and a conductor layer is laminated on both sides of a core substrate having a through hole. In the method for manufacturing a wiring board, the insulating resin layer of the resin-coated metal foil is made of a resin containing a filler, and when the resin-coated metal foil is laminated on the core substrate, the resin of the insulating resin layer is removed. A method for manufacturing a multilayer printed wiring board, characterized by flowing into and filling a through hole of the core substrate.

What is most noticeable in the present invention is that the insulating resin layer of the metal foil with resin is made of a resin mixed with a filler. Examples of the filler include aluminum hydroxide and silica. The insulating resin layer of the metal foil with resin is made of, for example, epoxy resin, polyimide resin, or the like, and the conductor layer is made of, for example, copper.

Next, the function and effect of the present invention will be described.
When laminating the resin-attached metal foil on the core substrate, as described above, the resin of the insulating resin layer flows into and fills the through holes of the core substrate. As described above, the resin of the insulating resin layer of the resin-attached metal foil contains a filler. Therefore, the resin filled in the through holes hardly shrinks at the time of curing or the like.

Therefore, the insulating resin layer above the through hole does not dent, and the conductor layer thereover does not dent. Thus, when a conductor pattern is formed by performing etching, metal plating, or the like on the conductor layer,
Accurate pattern formation can be performed, and occurrence of disconnection, short circuit, and the like can be reliably prevented.

In the above manufacturing method, the resin is filled in the through holes simultaneously with the lamination of the resin-attached metal foil on the core substrate, so that the production efficiency is excellent.

As described above, according to the present invention, it is possible to provide a method for manufacturing a multilayer printed wiring board excellent in production efficiency, which reliably prevents occurrence of disconnection, short circuit, and the like.

Next, as in the second aspect of the present invention, it is preferable that the filler mixed in the resin of the insulating resin layer is an acicular filler. This makes it possible to more reliably prevent the resin from shrinking. The needle-like filler has a length of about 5 to 20 μm and a diameter of 2 to 3 μm, for example.
m.

Next, an insulating resin layer is formed on both sides of a core substrate having conductor patterns on both sides of the insulating substrate and through holes for electrically connecting the conductive patterns to each other. In a multilayer printed wiring board obtained by laminating a resin-attached metal foil by laminating a conductor layer, the through-hole of the core substrate is filled with the resin of the insulating resin layer of the resin-attached metal foil. There is a multilayer printed wiring board characterized in that the resin of the insulating resin layer contains a filler.

In the multilayer printed wiring board, the resin of the insulating resin layer contains a filler. The resin is filled in the through holes of the core substrate. Therefore, the insulating resin layer above the through hole of the core substrate and the conductor layer on the upper surface thereof do not dent. Therefore, the conductor pattern in the conductor layer is
It is formed accurately and can reliably prevent disconnection and short circuit. In addition, the multilayer printed wiring board can be manufactured by filling the through holes with a resin at the same time as the lamination of the resin-attached metal foil on the core substrate, and thus has excellent production efficiency.

As described above, according to the present invention, it is possible to provide a multilayer printed wiring board excellent in production efficiency, which reliably prevents occurrence of disconnection, short circuit, and the like.

Next, as in the fourth aspect of the present invention, the filler blended in the resin of the insulating resin layer is preferably an acicular filler. Thereby, the shrinkage of the resin can be prevented more reliably, and a multilayer printed wiring board free from disconnection and short circuit can be obtained more reliably. The needle-like filler may have a length of about 5 to 20 μm and a diameter of about 2 to 3 μm, for example. In addition,
In the present invention, the core substrate also includes a multilayer printed wiring board having a conductor pattern inside.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A multilayer printed wiring board according to an embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS. As shown in FIGS. 1 and 2, the multilayer printed wiring board 1 of this embodiment
A metal with resin formed by laminating an insulating resin layer 31 and a conductor layer 32 on both sides of a core substrate 2 having conductor patterns 22 on both sides of an insulating substrate 21 and providing through holes 23 for electrically connecting these. It is manufactured by laminating foils 3.

The insulating resin layer 31 of the metal foil 3 with resin is
As shown in FIG. 1 (B), resin 3 containing filler 4
Consists of eleven. When laminating the metal foil 3 with resin on the core substrate 2, as shown in FIGS. 2C and 2D, the resin 311 of the insulating resin layer 31 flows into the through holes 23 of the core substrate 2. Fill.

The filler 4 mixed in the resin 311 of the insulating resin layer 31 is a needle-like filler and has a length of 5 to 5.
It has a diameter of about 20 μm and a diameter of about 2 to 3 μm. As the filler 4, aluminum hydroxide is used. The metal foil 3 with resin is a copper foil with resin formed by bonding an insulating resin layer 31 made of epoxy resin and a conductor layer 32 made of copper (Cu). The insulating resin layer 3
1 is about 60 μm, and the thickness of the conductor layer 32 is about 18 μm
It is. The thickness of the insulating substrate 21 in the core substrate 2 is about 450 μm, and the thickness of the conductor pattern 22 is about 30 μm.
μm, and the diameter of the through hole 23 is about 300 μm.

Next, a method of manufacturing the multilayer printed wiring board of this embodiment will be described in detail with reference to FIGS. First, Figure 1
As shown in FIG. 1A, a core substrate 2 having conductor patterns 22 on both sides of an insulating substrate 21 and a through hole 23 for electrically connecting the conductor patterns 22 is prepared. The through hole 23 is formed by applying metal plating 231 to the inner wall of a through hole penetrating the insulating substrate 21, and electrically connects the conductor patterns 22 on both surfaces of the core substrate 2.

Next, as shown in FIG. 1B, a metal foil 3 with resin is laminated on both surfaces of the core substrate 2. That is, as shown in FIG. 1B, the resin-attached metal foil 3 has an insulating resin layer 31 and a conductor layer 32 stuck on one side thereof.
The insulating resin layer 31 is disposed so as to be in contact with both surfaces of the core substrate 2 so as to face each other. By applying pressure while heating this, the core substrate 2 and the metal foil 3 with resin are joined, and the resin 311 of the insulating resin layer 31 flows into and fills the through holes 23 of the core substrate 2 (FIG. 2 (C),
(D)).

As a result, as shown in FIG. 2D, the resin 311 containing the filler 4 is filled in the through hole 23. Next, the resin 211 disposed on both surfaces of the core substrate 2 and the resin 211 filled in the through holes 23 are thermally cured. Thereafter, the conductor layer 31 of the resin-attached metal foil 3 is etched, plated, or the like to form a conductor pattern 321 as shown in FIG. In some cases, the insulating resin layer and the conductor layer are similarly laminated.

Thus, the multilayer printed wiring board 1 of this embodiment is obtained (FIG. 2E). That is, in the multilayer printed wiring board 1, the resin 311 of the insulating resin layer 31 of the metal foil 3 with resin is filled in the through holes 23 of the core substrate 2. The resin 311 contains a filler 4, and the filler 4 is an acicular filler.

Next, the operation and effect of this embodiment will be described. In the method of manufacturing the multilayer printed wiring board 1 of the present embodiment, when laminating the resin-attached metal foil 3 on the core substrate 2, the resin 311 of the insulating resin layer 31 is transferred to the through-hole of the core substrate 2 as described above. 23 to be filled (see FIG. 2).
(C), (D)). As described above, the insulating resin layer 31
The resin 311 is obtained by blending the filler 4. Therefore, the resin 311 filled in the through hole 23 is
Hardly shrinks during curing.

Therefore, the insulating resin layer 31 above the through hole 23 does not dent, and the conductor layer 32 thereover does not dent (FIG. 2D). Thus, when the conductor pattern 32 is formed by etching, metal plating, or the like, the conductor layer 32, an accurate pattern can be formed, and occurrence of disconnection, short circuit, and the like can be reliably prevented.

In the above-described manufacturing method, the resin 311 can be filled into the through holes 23 at the same time as the lamination of the metal foil 3 with resin on the core substrate 2. I have.

Since the filler 4 contained in the resin 311 is a needle-like filler, the shrinkage of the resin 311 can be more reliably prevented. Thereby, the multilayer printed wiring board 1 free from disconnection and short circuit can be obtained more reliably.

As described above, according to the present embodiment, it is possible to provide a multilayer printed wiring board excellent in production efficiency, which reliably prevents occurrence of disconnection, short circuit, and the like, and a method of manufacturing the same.

Embodiment 2 In this embodiment, as shown in FIG. 3, the amount of depression of the insulating resin layer above the through hole, that is, the amount of depression of the conductor layer in the multilayer printed wiring board according to the present invention was measured. is there. The dent amount is the dent amount A shown in FIG.
It is.

In this embodiment, a metal foil with a resin is laminated on both sides of the core substrate by the method described in the first embodiment, and the resin of the insulating resin layer is thermally cured to obtain a multilayer printed wiring board.
That is, a filler is mixed in the resin of the insulating resin layer of the metal foil with resin. At this time, the thickness of the insulating substrate of the core substrate was set to 380 μm, 550 μm, and 920 μm, and the multilayer printed wiring board was manufactured, respectively.
1, Sample E2 and Sample E3.

In each of the samples E1 to E3, the thickness of the conductor pattern on the core substrate was about 25 μm.
The diameter of the through hole is about 300 μm. The thickness of the insulating resin layer in the metal foil with resin is 60 μm, and the thickness of the conductor layer is about 12 μm. Others are the same as in the first embodiment.

On the other hand, for comparison, a multilayer printed wiring board was manufactured using a resin-coated metal foil having an insulating resin layer containing no filler (see FIGS. 4 and 5). this,
Comparative Sample C1, Comparative Sample C2, and Comparative Sample C3 were used. The comparative samples C1 to C3 are the same as the samples E1 to E3 except that no filler is added to the resin of the insulating resin layer.

The above samples E1 to E3 and comparative samples C1 to C1
For C3, the amount A of depression of the conductor layer above the through hole was measured. FIG. 3 shows the measurement results.
In the figure, E1 to E3 plotted with black circles correspond to sample E.
The measurement results of 1 to E3 are shown.
C3 indicates the measurement results of the comparative samples C1 to C3.

As can be seen from FIG. 3, the comparative samples C1 to C
No. 3 has a large dent amount A, and 7 μm for the comparative sample C3.
A large amount of nearby depression was measured. On the other hand, sample E
In E1 and E2, almost no dent was formed, and also in Sample 3, only a dent of about 1 μm was formed. From the above results, it can be understood that the multilayer printed wiring board of the present invention can reliably prevent the insulating resin layer above the through hole and the conductor layer thereabove from being dented.

[0040]

As described above, according to the present invention, disconnection,
It is possible to provide a multilayer printed wiring board excellent in production efficiency, which reliably prevents occurrence of a short circuit or the like, and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1A is a cross-sectional explanatory view of a core substrate, illustrating a method of manufacturing a multilayer printed wiring board according to a first embodiment;
(B) Sectional explanatory drawing of a core board and metal foil with resin.

FIGS. 2A and 2B are cross-sectional explanatory views illustrating the inflow of a resin into a through-hole, a cross-sectional explanatory view illustrating a state after the resin is cured, and FIG. Sectional drawing of the multilayer printed wiring board after.

FIG. 3 is a diagram illustrating a measurement result of a dent amount according to a second embodiment.

FIGS. 4A and 4B are cross-sectional explanatory views of a core substrate and a metal foil with resin, illustrating a method of manufacturing a multilayer printed wiring board in a conventional example.

5A and 5B are cross-sectional explanatory views illustrating a state in which a resin flows into a through hole in a conventional example, and FIG. 5D is a cross-sectional explanatory view illustrating a state after the resin is cured.

[Explanation of symbols]

 1. . . 1. multilayer printed wiring board, . . Core substrate, 21. . . Insulating substrate, 22. . . Conductor pattern, 23. . . 2. through hole, . . 30. metal foil with resin; . . Insulating resin layer, 311. . . Resin, 32. . . 3. conductor layer; . . Filler,

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (4)

[Claims] 1. A method of manufacturing a multilayer printed wiring board by laminating a resin-attached metal foil obtained by laminating an insulating resin layer and a conductor layer on both surfaces of a core substrate provided with through holes. The insulating resin layer of the attached metal foil is made of a resin mixed with a filler. When the resin-attached metal foil is laminated on the core substrate, the resin of the insulating resin layer flows into and fills the through holes of the core substrate. A method for manufacturing a multilayer printed wiring board. 2. The method according to claim 1, wherein the filler compounded in the resin of the insulating resin layer is an acicular filler. 3. A resin-attached metal foil in which an insulating resin layer and a conductor layer are attached to both sides of a core substrate having conductor patterns on both sides of an insulating substrate and through holes for electrically connecting the conductor patterns. In the multilayer printed wiring board obtained by laminating the resin, the through-hole of the core substrate is filled with the resin of the insulating resin layer of the metal foil with resin, and the resin of the insulating resin layer is A multilayer printed wiring board characterized by comprising a filler. 4. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein the filler compounded in the resin of the insulating resin layer is an acicular filler.